The technology of the present disclosure relates to an image reading device and an image forming apparatus including the same.
Conventionally, as an image reading device mounted in an image forming apparatus such as a copy machine, there has been known a device including a scanner casing, an image reading unit, and a document pressing member. The scanner casing is provided on an upper surface thereof with a contact glass on which a document is placed. The image reading unit is accommodated in the scanner casing and reads an image of the document on the contact glass. The document pressing member is a member for pressing the document on the contact glass. The document pressing member is mounted at a rear end portion thereof with a rotating metal fitting. The rotating metal fitting is connected to a stationary metal fitting via a hinge shaft. The stationary metal fitting is fixed to an upper end portion of a leg part extending in a vertical direction. The leg part is inserted into a support hole formed at a rear end portion of an upper surface of the scanner casing. Furthermore, the aforementioned leg part slides in the aforementioned support hole in the vertical direction, so that it is possible to cope with the size of a thickness of the document. A sidewall of the support hole, for example, is formed by a cylindrical part integrally formed with the scanner casing.
The aforementioned image reading device further includes a holding mechanism that holds an opening angle of the document pressing member at an arbitrary angle. The holding mechanism includes a compression spring arranged between the rotating metal fitting and the stationary metal fitting, a retainer that holds the compression spring, and an abutting shaft supported to the stationary metal fitting to abut an inclined surface of the retainer. When the opening angle of the document pressing member is within a predetermined range, the document pressing member is urged to an opening side by urging force of the compression spring, so that the weight of the document pressing member and the urging force of the compression spring are balanced. As a consequence, the document pressing member is held at an arbitrary opening angle.
In the aforementioned image reading device, various technologies have been proposed in order to reduce collision sound when the document pressing member is closed. As one of these various technologies, there is a technology for allowing an inner diameter of the support hole to be larger than an outer diameter of the leg part. In this way, the leg part can be inclined to the document pressing member side in the support hole and can be stretched, resulting in the suppression of a speed when the document pressing member is closed.